thanks for all the advise yesturday I found out why the check engine light is on and the car is idling up and down I was trying to set the fuel pressure on the regulator and then the car started the up and down idle thing so i looked at the pressure gauge it was jumping from 20-60 back and forth as the idle was going up and down thats probably the problem with hesitation its loosing fuel pressure anybody know why this would happen its a 93 mustang gt please help!!!!!! it has holley adjustable fuel pressure regulator it also has a hypertech chip I didn't put it in could that be faulty I don't know I just throwing stuff out now
help fuel pressure problems!!!!!!
- Thread starter jodybennettii
- Start date
What codes did you get, or have you posted them and gotten an answer?
Check fuel pressure – remove the cap from the Schrader valve behind the alternator and connect fuel pressure test gauge to Schrader valve. The fuel pressure regulator is located on the passenger side of the car behind the throttle body.
Disconnect the small vacuum line from the fuel pressure regulator and plug the line. Leave the port where you removed the line uncapped and open to the atmosphere.
Start the car and observe the pressure: you should see 37-41 PSI at idle.
Be sure to unplug and reconnect the vacuum line to the fuel pressure regulator when you have finished your tests.
Fuel pump pressure test
Disconnect the larger of the two fuel lines up by the Schrader valve. It is the return line and does not have the Schrader valve on it. Find a piece of rubber fuel hose and clamp it on the return line coming from the regulator. Stick a bolt in the other end of the hose and make sure that all your connections are tight and leak proof as possible. Be extremely caeful that your test connections have no leaks. There is a definite fire hazard when you do this test When this powers up, you don't want fuel squirting everywhere. Hook up the fuel pressure test gauge. Turn the ignition switch on and watch for leaks. You may want to use a helper inside the car to cut the switch off quickly if you have a leak. To trick the fuel pump into running, find the ECC test connector and jump the connector in the Upper RH corner to ground.
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Caution!!! You have blocked the return line for the fuel pump! Pressure will rise very quickly past safe levels with a good pump
If the pressure goes up past 55 PSI, the pump is good and the fuel pressure regulator is bad. If the fuel pressure does not hit 55PSI or more in a few seconds, the pump is bad or you have electrical problems.
Check fuel pressure – remove the cap from the Schrader valve behind the alternator and connect fuel pressure test gauge to Schrader valve. The fuel pressure regulator is located on the passenger side of the car behind the throttle body.
Disconnect the small vacuum line from the fuel pressure regulator and plug the line. Leave the port where you removed the line uncapped and open to the atmosphere.
Start the car and observe the pressure: you should see 37-41 PSI at idle.
Be sure to unplug and reconnect the vacuum line to the fuel pressure regulator when you have finished your tests.
Fuel pump pressure test
Disconnect the larger of the two fuel lines up by the Schrader valve. It is the return line and does not have the Schrader valve on it. Find a piece of rubber fuel hose and clamp it on the return line coming from the regulator. Stick a bolt in the other end of the hose and make sure that all your connections are tight and leak proof as possible. Be extremely caeful that your test connections have no leaks. There is a definite fire hazard when you do this test When this powers up, you don't want fuel squirting everywhere. Hook up the fuel pressure test gauge. Turn the ignition switch on and watch for leaks. You may want to use a helper inside the car to cut the switch off quickly if you have a leak. To trick the fuel pump into running, find the ECC test connector and jump the connector in the Upper RH corner to ground.
Caution!!! You have blocked the return line for the fuel pump! Pressure will rise very quickly past safe levels with a good pump
If the pressure goes up past 55 PSI, the pump is good and the fuel pressure regulator is bad. If the fuel pressure does not hit 55PSI or more in a few seconds, the pump is bad or you have electrical problems.
wait till you read this
OMG you wont believe this but I have never changed the sparkplugs in this car so i thought give that a shot I have had this car since 2003 and just now found out that the spark plug on the drivers side rear sparkplug was the wrong one it was too long it looks like it hit the piston the little L shaped tip was broke off and so was the tip it sparked off of can u believe that the car has NEVER ran this good never had this much power thanks for all your help Jody
OMG you wont believe this but I have never changed the sparkplugs in this car so i thought give that a shot I have had this car since 2003 and just now found out that the spark plug on the drivers side rear sparkplug was the wrong one it was too long it looks like it hit the piston the little L shaped tip was broke off and so was the tip it sparked off of can u believe that the car has NEVER ran this good never had this much power thanks for all your help Jody
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